Apparatus for daylight developing, fixing and washing of light sensitive strips



Nov. 6, 1956 M. ESJAK 2 APPARATUS FOR DAYLIGHT DEVELOPING, FIXING ANWASHING OF LIGHT SENSITIVE STRIP Filed NOV. 19. 1951 2 Sheets-SheetNF/:15 3 E Z 1 *6 INVENTOR:

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HIS ATfORNEYS Nov. 6, 1956 M. LESJAK 2,769,381

APPARATUS FOR DAYLIGHT DEVELOPING, FIXING AND WASHING OF LIGHT SENSITIVESTRIPS- 2 Sheets-Sheet 2 Filed Nov. 19. 1951 INVENTOR. MKIHAEL.LEfiJAIA, DECEASED. By BY EABETTE LEfidAK ExEcu-rmx HIS ATTORNEYS UnitedStates Patent APPARATUS FOR DAYLIGHT lNG AND WASHING OF STRIPS MichaelLesjak, deceased, late of Goggingen, Germany,

by Babette Viktoria Lesjak, executrix, Goggingen, Germany DEVELOPING,FIX- LIGHT SENSITIVE The present invention relates to apparatus fordevelop ing, fixing and washing of light sensitive film strips,particularly roll films, in daylight.

So-called daylight developing tanks have long been known. A verysuccessful type is described in the U. S. Patent No. 2,082,962 issued tothe inventor herein and another. In that known type a take-up axle withspirally grooved flanges is provided, the distance between the flangesbeing such that the edges of the film strip are held within the spiralgrooves. Inasmuch as the film is led into the grooves from the inner endof the spiral outwards, a special guide must be provided that pressesthe edges of the film together sufliciently so that it can be drawn pastthe flanges to the inner end of the spiral. This guide is swingablymounted between the spirally grooved flanges near the point at which theroll film is drawn into the developing chamber. It is furthermorenecessary to provide a pull-in band fixed at one end to the axle andprovided at the other end with a clamp for attachment to the leading endof the film. This pull-in band serves the purpose of drawing the end ofthe film through the guide and into the spiral grooves.

The principal object of this invention is to simplify the abovedescribed apparatus by dispensing with many of its parts such as thespirally grooved flanges, the guide and the pull-in band.

In the preferred embodiment of the invention there is utilized theinherent spring action of the film to produce a loose spiral within thedeveloping chamber by winding it up upon a rotatable axle in thedeveloping chamber in the opposite direction to that in which the filmstrip is compactly rolled upon the usual film spood or in the usualcartridge after exposure. The take-up axle in the developing chamber hassubstantially straight sides, i. e. it is not provided with thecustomary spirally grooved flanges, so that edges of the film stripwound thereon are unconfined. This take-up axle bears the film attachingmeans, thus eliminating the usual pull-in band and clamp. It is furtherdistinguished from the flanged takeup axles of the known apparatus bybeing rotatable in both directions. This constitutes an importantfeature of the simplified apparatus.

In operating this apparatus, the film is first wound up upon the axle inthe form of a loose spiral with unconfined edges as described above.Thereupon the direction of rotation is reversed and the reverse rotationis continued until the film has become wound upon the axle in theopposite direction. When the direction of rotation is reversed the filmis bowed at the axle reversing its direction, and this bow wanders fromthe inside to the outside of the loose spiral. The movement of this bowhelps to agitate the treating liquid, thus insuring rapid and uniformtreatment. It is desirable to repeat the successive windings of the filmin opposite directions a number of times to insure that the desiredtreatment such as developing, fixing or washing is complete.

The apparatus may now be described in somewhat greater detail. Itconsists of the usual developing chamber that may be closed in alight-tight manner by means Patented Nov. 6, 1956 of a cover, but whichwhen so closed still permits filling and emptying of the treatingliquid. In the side walls of this container there is centrally mounted atake-up axle provided with a film attaching clamp. This axle isrotatable in both directions and can be actuated from outside thecontainer by means of a protruding button or crank, so that the filmthat is attached to the axle may readily be wound thereon by drawing itfrom a preliminary roll film chamber that adjoins the developing chambernear the top. This roll film chamber of the daylight developing tank isseparated from the developing chamber by a partition, in order toprevent entrance of the treating liquid. The upper edge of thispartition is removed from the take-up axle by a distance that is lessthan the length of the leading end of the film strip. By leading end ismeant that portion of the film strip which is required for introducingit into the camera and upon which, therefore, no exposure can be made.According to this invention the space within the developing chambershould preferably be of such size in relation to the diameter of thetake-up axle, that the film strip can be wound successively in reversedirections through its full length upon the take-up axle in the form ofa loose spiral. Suflicient clearance should be provided to accommodatethe bow that is formed in the film when the direction of the winding isreversed. In order to minimize contact, particularly of the emulsionside of the film, with the walls of the developing chamber and thecover, ridges or like projections are arranged thereon that will permitthe film strip to make contact only at its edge zones.

It is preferred to provide a holding device for the film strip, that canbe actuated from outside the tank, in the neighborhood of the partitionbetween the roll film chamber and the developing chamber where the filmenters the latter. This holding device may be used to prevent thetrailing end of the film strip from being drawn into the developingchamber and also makes it possible to treat only a front portion of thefilm strip. While adequate space must be provided for formation of theloose spiral and of the film bow, the distance between the circumferenceof the take-up axle and the inner walls and cover of the container inall directions should not substantially exceed the diameter of thetake-up axle. Thus it is insured that upon alternate reverse winding ofthe film, the outermost coil of the film quickly finds support againstthe inner walls of the developing container and the Wandering film bowformed upon changing the direction of rotation does not deform the filmspiral in one direction, but rather wanders uniformly from the innerwindings to the outer winding of the spiral while agitating the treatingsolution in a lively manner.

It is desirable to make the take-up axle removable from the developingchamber to facilitate clamping of the leading end of the film thereto.This may easily be accomplished by providing supports in the side wallsthat are open at the top and making the actuating knob or handleretractable. Another desirable feature is to provide an indicatingdevice of known construction, in order to be able to determine whichlength of film has been Wound into the developing chamber. Furthermore,it is easily possible to provide a cutting device for the film betweenthe roll film chamber and the developing chamber.

A particular embodiment of the daylight developing tank in accordancewith the invention will now be described with reference to theaccompanying drawings in which it is illustrated. Obviously theinvention is not limited to the details shown therein. In thesedrawings: Fig. l is a plan View of the daylight developing tank with itscover removed;

Fig. 2 is a vertical cross section of the daylight developing tank withthe cover thereon, showing the leading end of the film clamped to thetake-up axle at the beginning of the counterclockwise winding; I

Fig. 3 is the same cross section, however, showing the position of thefilm in the developing chamber at the beginning of the clockwisewinding; and

Fig. 4 is a side view of the daylight developing tank.

In the preliminary roll film chamber 1 adjacent the developing chamber2' there is placed a roll film spool or cassette 3 and the leading endof the film d is attached to the take-up axle 5 with the aid of thechamp 6. The developing chamber is charged with treating liquid 7 eitherbefore or after such clamping, and the light-tight cover 8 is placedover both chambers. Upon turning of the crank 9 in a counterclockwisedirection, the film is wound upon the axle 5 in the spiral formillustrated inFig. 2. Since such counterclockwise Winding is contrary tothe inherent tendency of the roll film to curl in the oppositedirection, the film lies about the axle in the form of a loose spiralwith unconfined edges. As a counting device there may serve, forexample, the measuring roller 14 that is mounted in the neighborhood ofthe partition 10 between the two chambers and whose teeth grip into theperforations of the film strip. Thus the number of frames that have beendrawn into the developing tank may be indicated upon the outside dial11, for example by means of a Maltese cross-like gear. After the filmhas been completely wound about the take-up axle 5, the direction ofrotation is reversed, and the film is then wound about the axle in aclockwise direction as indicated in Fig. 3. Upon reversing the directionof rotation an S-shaped bow 4a is formed in the inner winding of thefilm spiral which progressively moves towards the outside and thusfacilitates an intimate contact between the treating liquid and the filmstrip.

In order to make sure that the outer winding of the film strip comesinto contact with the walls and cover of the developing chamber only atthe edge zones of the film, thus avoiding damage to the picture, theridges 2a and 8a are provided on such walls and cover which permitcontact only at the zones of perforation of the film strip.

It should also be mentioned that the film is preferably held fast in theneighborhood of the partition 10 by means of the holding device 12,before it is wound in the reverse direction (clockwise). This holdingdevice may consist for example of a screw with a rubber head thatpresses the film against -a projection 1951 on the partition. It is, ofcourse, possible to employ other types of holding devices such as aswingable bow or the like for this purpose. The cover 8 of thedeveloping tank is so formed that it is possible to charge thedeveloping chamber 2 with treating liquid and then to pour out the samethrough the trough 13 without breaking the light-tight closure.

Thus the developing solution can be replaced by a fixing solution andfinally by wash water, so that the development, fixing and washing ofthe film may be performed successively without removing the film fromthe developing chamber. If desired the film may be removed after fixingand washed in a stretched condition in the-usual washing vats. Afterwashing, thefilm should be dried in this position. Ifdesired, thetake-up axle 5 which is removable may be employed as 'a Weight to holdthe film fications may be made of the details described withoutdeparting from the spirit and scope of the invention. All suchmodifications are to be included within the scope of the appended claimsunless expressly excluded by the limitations contained therein.

What is claimed is:

1. A daylight developing tank for roll film strips comprising ahorizontal preliminary roll film chamber, an adjacent horizontalcylindrical developing chamber for containing a treating solution, apartition between said chambers over whose upper edge the film passesduring its transfer from said preliminary to said developing chamber, alight-tight cover for said tank covering both said chambers, areversibly rotatable axle horizontally mounted in the circular sidewalls of said horizontal cylindrical developing chamber, said axleincluding a centrally located groove of a width along said axle at leastequal to the width of said film strip, said groove providing asubstantially flat clamping surface in a plane parallel to the axes ofsaid axle, a clamping means mounted upon said flat clamping surface forsecuring the leading end of a film strip to said surface, a holdingdevice mounted through said cover adjacent the upper edge of saidpartition for securing the trailing end of said film strip to said upperedge of said partition, the distance between the circumference of saidaxle and the surrounding inner Walls and cover of said developingchamber being substantially equal to the diameter of said axle to insureconsistent formation of a wandering bow upon reversed rotations of theaxle, and external winding means connected to said axle for rotatingsaid axle to draw the film strip from said preliminary chamber over saidpartition through said treating solution and when said trailing end ofsaid film strip is secured between said holding device and said upperedge of said partition to form said wandering bow upon reversedrotations of said axle whereby said film strip is agitated through saidtreating solution.

2. A daylight developing tank as set forth in claim 1 wherein said axleis removably mounted within said cylindrical developing chamber and saidwinding means is removably connectable to said axle to permit removal ofsaid film and attached axle from said developing chamber to be washed inan unwound elongated condition in a conventional washing vat with saidtake-up axle being employed as a weight to hold said film strip in saidelongated condition.

3. A daylight developing tank as set forth in claim 1 wherein the innerwalls and cover of the developing chamber are provided with a pair ofridges spaced to limit the contact of the tank wall to the perforatededge zone of the film to prevent damage to the coated portions of thefilm.

4. A daylight developing tank as set forth in claim 1 wherein a countingdevice is mounted within said tank to engage said film at a pointbetween said preliminary chamber and said axle, said counting deviceextending externally to provide a visible indication of the amount offilm unwound within said developing chamber.

References Cited in the file of this patent UNITED STATES PATENTSOrrnond May 29,

